1. Field of the Invention
This invention relates to expandable section tubes and to methods of making same and more particularly to balloon catheters.
2. Background Information
Tubes having expandable thin walled sections have many known uses, particularly in medicine where such tubes may be used as drainage catheters, plaque compression devices for use in blood vessel treatments, blockage devices for blocking flow through various bodily passageways, irrigation instruments and the like. Typical such devices include catheters of the type generally known as Foley catheters utilizing a dual lumen elastomer catheter having a balloon section adjacent one end. One lumen is directed to the interior of the balloon section formed on an outer wall of the catheter and is used for inflating and deflating the balloon section. Such catheters have known disadvantages in that the addition of a second lumen and the necessary separating walls separating the balloon lumen from the main lumen reduces the cross section dimension of the main lumen. Such devices may be utilized in procedures requiring a maximum lumen diameter in association with a minimum overall outer diameter. Due to the use of dual lumens for a given outer diameter, the main lumen inner diameter is necessarily restricted. Additionally, such known catheters, to the extent that the expandable balloon section is spaced from the distal end, provide disadvantages in that the end section projecting distally of the balloon may interfere with desired procedures, such as drainage, or may provide an irritant in situations where the catheter is left in place for a period of time, such as, for example, when it is used as a long-term bladder drainage device where the bladder wall opposite the catheter may become irritated by the catheter distal tip when the bladder is collapsed.
U.S. Pat. No. 3,050,066 discloses a catheter device which improves upon the Foley type catheter in that the balloon section is located at a distal end of two telescoping tube sections, the balloon section forming a joinder wall between the inner tube and the outer tube such that the annulus between the inner tube and the outer tube provides a communication to the interior of the balloon section for inflation and deflation. In such a device the balloon section is located immediately at the distal end of the catheter. While this construction offers advantages over a Foley type catheter, it is particularly difficult to manufacture and use since it requires a connecting joint to be formed between the connection of one of the inner or outer tube ends and the balloon. This joint, which is used to connect the balloon end to the inner tube when the balloon is formed as a soft expanded section at the end of the outer tube, naturally provides an assembly which is difficult to manufacture and which has an inherent weakness at the joint allowing the possibility of leakage or rupture.
It would therefore be an advance in the art to provide an expandable section tube where the expandable section is formed integrally with portions of the tube extending to both sides of the expandable section and to utilize such tubes in the formation of a balloon catheter having a balloon section located at a terminal distal end of the catheter.